Hey!
Good job as far as I can tell - good for a first game.
Things you should work on are the graphics obviously and your difficulties. I played until 7 and lost (I'm so full of rage I didn't get the medal). Now I'm back at Difficulty 4 and the bot is seriously playing like Difficulty 7. This wasn't in my first run where I got to 7. It seems like every difficulty is the last one you died after you died. Like even Difficulty 3 is killing me right now. Maybe a bug?